Female one end, male the other — reducing and converting between metric, UNC/UNF, BSP and NPT. Round-bodied or a hex body for a wrench, machined to your two threads.
A female-to-male adapter has an internal (female) thread on one end and an external (male) thread on the other. It screws over a male thread on one side and into a female port on the other — reducing and converting the size in a single part. When the body carries wrench flats, this same part is called a hex reducing bushing; without them, a round reducer. It is the workhorse of pipe, hydraulic and instrument connections.
If instead you need a male thread on both ends, you want a male-to-male adapter; unsure which gender, start with the thread adapter types guide.
| Choice | Options | When to pick it |
|---|---|---|
| Body form | Round, or hex for a spanner | Hex where the joint is torqued (pipe, hydraulic) |
| Seating | Shoulder stop, or fully threaded (shoulderless) | Shoulder for a set position; shoulderless for max engagement |
| Female end | Metric, UNC/UNF, BSP (G / Rc), NPT | Screws onto the male part you already have |
| Male end | Metric, UNC/UNF, BSP, NPT, parallel or tapered | Screws into the port you are adapting to |
| Sealing | Tapered self-seal, O-ring groove, bonded seat | Matched to the pressure and medium |
Standards we cut to: ISO 261 / DIN 13 (metric), ASME B1.1 (UNC/UNF), ISO 228-1 (BSP parallel), ISO 7-1 · ASME B1.20.1 (BSP taper / NPT), BS 84 (Whitworth).
| Material | Density | Why choose it for a reducing bushing |
|---|---|---|
| Brass (CZ121 / C360) | 8.5 g/cm³ | The default — free-machining, seals well, low cost |
| Stainless 303 | 7.9 g/cm³ | Free-machining stainless, general corrosion |
| Stainless 316L | 8.0 g/cm³ | Marine, chemical, washdown, semiconductor |
| Steel (zinc-plated) | 7.85 g/cm³ | High-pressure hydraulic strength at low cost |
| Aluminum 6061 | 2.70 g/cm³ | Light, low-pressure, weight-sensitive |
| Titanium Gr5 | 4.43 g/cm³ | Light + corrosion-proof — premium and aerospace |
A hex reducing bushing, female 1/2" BSP in, male 3/8" NPT out, in 316L for a washdown line, machined to ISO 228 and ASME B1.20.1 and gauged both ends.
A female-to-male adapter, female G1/2 to male M20×1.5, with a bonded-seal shoulder. Also see our sensor thread adapters for gauge and transducer ports.
Shoulderless reducers for tight depth are a routine turning job — brass, to your exact two threads, one-off or in a batch.
Reducing between metric and inch? A female-to-male that also crosses systems is covered in depth on our metric-to-imperial thread adapters page. Send the two threads and we confirm the form and sealing.
An adapter with an internal (female) thread one end and an external (male) thread the other — it screws over a male thread and into a female port, reducing and converting in one part.
Yes — a female-to-male adapter with a hex body so it can be torqued with a wrench, common on pipe and hydraulic ports. We machine both round and hex bodies.
Yes — female BSP to male NPT, female metric to male UNF, coarse to fine. Each end is machined independently, parallel or tapered as needed.
Both. Shoulder stop for a set seating position; fully threaded (shoulderless) for maximum engagement where depth is tight. To your drawing.
The female thread and the male thread with pitches, parallel or tapered, round or hex body, material — or the two parts you're joining. Quote in 24 hours.
Tell us the female and male ends, and hex or round. Engineers reply in 24h.
// Qty & price
1 pc
Sample price
Confirm fit before a run
3–50
Unit price drops
Setup cost shared
50+
Best price
All tiers quoted upfront
Female one end, male the other — round or hex, sealed for pressure. Any thread combination, machined to your two sizes. Quote in 24 hours.